JP2017029912A - Separation membrane element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a separation removal performance of a separation membrane element when being operated over a long duration.SOLUTION: The separation membrane element is provided that comprise: a water collection pipe; a separation membrane which has a surface of the supply side and a surface of the permeation side and is wound around the water collection pipe and a plurality of protrusions provided on the surface of the permeation side of the separation membrane. The protrusions are composed of a protrusion group and separated protrusions, the separated protrusions are arranged on the side outer than a longitudinal direction end part of the water collection pipe, of at least one side of the protrusion group, an interval of the protrusions on the protrusion group is 0.1 mm or more and 1.0 mm or less and an interval in the longitudinal direction of the water collection pipe between the protrusion group and the separated protrusion is 10 mm or more and 50 mm or less.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a separation membrane element used for separating components contained in a fluid such as liquid and gas.

  In the technology for removing ionic substances contained in seawater, brine, and the like, in recent years, the use of separation methods using separation membrane elements is expanding as a process for saving energy and resources. The separation membrane used for the separation membrane element is selectively used depending on the target separation component and separation performance.

  As the separation membrane element, various shapes such as a spiral type, a hollow fiber type, a plate-and-frame type, a rotating flat membrane type, and a flat membrane integrated type have been proposed according to applications and purposes.

  In the spiral type separation membrane element, in general, a polymer net is mainly used as a supply-side channel material in order to form a supply-side fluid channel. Further, as the permeation side channel material, a knitted member called a tricot having a smaller interval than the supply side channel material is used for the purpose of preventing the separation membrane from dropping and forming the permeation side channel.

  Further, as in Patent Document 1, a channel material in which protrusions are arranged on a sheet other than a tricot is disclosed, and the width of the protrusions is changed from the viewpoint of pressure resistance.

Japanese Patent Laying-Open No. 2015-6661

  However, since the leaf adhesive is consumed more than necessary at the time of winding in the manufacturing process of the separation membrane element described above, the consumption of the leaf adhesive may be large.

In order to solve the above problems, the separation membrane element of the present invention is:
A separation membrane element comprising a water collection pipe, a separation membrane wound around the water collection pipe, and a protrusion fixed to a base material or sheet. And
The spacing protrusion is disposed outside a longitudinal end portion of the water collecting pipe of at least one of the protrusion group,
The interval between the protrusions in the protrusion group is 0.1 mm or more and 1.0 mm or less,
In the separation membrane element, the interval between the protrusion group and the separation protrusion in the longitudinal direction of the water collecting pipe is 10 mm or more and 50 mm or less.

  According to the present invention, it is possible to efficiently apply the leaf adhesive on the separation membrane element.

It is a disassembled perspective view which shows one form of a separation membrane leaf. It is a top view which shows the separation membrane provided with the protrusion continuously provided in the surrounding direction of the separation membrane. It is a top view which shows the separation membrane provided with the protrusion provided discontinuously in the surrounding direction of the separation membrane. It is sectional drawing of the separation membrane of FIG. 2 and FIG. It is sectional drawing which shows schematic structure of a separation membrane main body. It is a development perspective view showing one form of a separation membrane element. It is a top view which shows one form of the sheet | seat or separation membrane provided with the protrusion group continuously provided in the surrounding direction of the separation membrane, and the separation protrusion. It is a partial expansion | deployment top view of the sheet | seat or separation membrane provided with the protrusion group provided in the surrounding direction of the separation membrane, and the separation protrusion. It is a figure which shows an example of the method of arrange | positioning a permeation flow path material to a membrane leaf.

  Hereinafter, embodiments of the present invention will be described in detail.

[1. Separation membrane)
(1-1) Overview of Separation Membrane A separation membrane is a membrane that can separate components in a fluid supplied to the surface of the separation membrane and obtain a permeated fluid that has permeated the separation membrane. In the following embodiments, protrusions are fixed to the permeation side surface of the separation membrane. Since the protrusion is integrated with the separation membrane by fixing, the protrusion can be regarded as a separation membrane including the protrusion. Therefore, below, in order to distinguish a protrusion and a membrane part, a membrane part may be called a "separation membrane main body." That is, the separation membrane can also be expressed as including a separation membrane main body and a protrusion disposed on the separation membrane main body.

  As an example of such a separation membrane, the separation membrane 1 of the present embodiment includes a separation membrane body 2 and a permeation protrusion 3 as shown in FIG. The separation membrane body 2 includes a supply-side surface 21 and a permeation-side surface 22.

  In this document, the “supply side surface” of the separation membrane main body means a surface on the side to which raw water is supplied out of the two surfaces of the separation membrane main body. The “transmission side surface” means the opposite side surface. As will be described later, when the separation membrane main body includes the base material 201 and the separation functional layer 203 as shown in FIG. 7, generally, the surface on the separation functional layer side is the surface on the supply side, Is the surface on the transmission side.

  The protrusion 3 is provided on the transmission side surface 22 so as to form a flow path. Details of each part of the separation membrane 1 will be described later.

  The x-axis, y-axis, and z-axis direction axes are shown in the figure. As shown in FIG. 1 and the like, the separation membrane body 2 is rectangular, and the x-axis direction and the y-axis direction are parallel to the outer edge of the separation membrane body 2. The x direction corresponds to the width direction of the separation membrane, and the y axis direction corresponds to the surrounding direction. In particular, in the example shown in the drawings, the film forming direction (MD) matches the winding direction. A direction perpendicular thereto is displayed as CD (Cross direction) in the drawing.

(1-2) Separation membrane body <Overview>
As the separation membrane body, a membrane having separation performance according to the method of use, purpose and the like is used. The separation membrane body may be formed of a single layer or a composite membrane including a separation functional layer and a substrate. As shown in FIG. 5, in the composite membrane, a porous support layer 202 may be formed between the separation functional layer 203 and the base material 201.

<Separation function layer>
The thickness of the separation functional layer is not limited to a specific numerical value, but is preferably 5 nm or more and 3000 nm or less in terms of separation performance and transmission performance. In particular, in the case of a reverse osmosis membrane, a forward osmosis membrane, and a nanofiltration membrane, the thickness is preferably 5 nm or more and 300 nm or less.

  The thickness of the separation functional layer can be based on the conventional method for measuring the thickness of the separation membrane. For example, the separation membrane is embedded with resin, and an ultrathin section is prepared by cutting the separation membrane, and the obtained section is subjected to processing such as staining. Thereafter, the thickness can be measured by observing with a transmission electron microscope. Further, when the separation functional layer has a pleat structure, it can be measured at intervals of 50 nm in the cross-sectional surrounding direction of the pleat structure located above the porous support layer, and the number of pleats can be measured to obtain 20 from the average. it can.

  The separation function layer may be a layer having both a separation function and a support function, or may have only a separation function. The “separation function layer” refers to a layer having at least a separation function.

  When the separation functional layer has both a separation function and a support function, a layer containing cellulose, polyvinylidene fluoride, polyether sulfone, or polysulfone as a main component is preferably applied as the separation functional layer.

  In this document, “X contains Y as a main component” means that the Y content in X is 50% by mass, 70% by mass, 80% by mass, 90% by mass, or 95% by mass. It means that it is more than%. In addition, when there are a plurality of components corresponding to Y, the total amount of these components only needs to satisfy the above range.

  On the other hand, as the porous support layer separating functional layer, a crosslinked polymer is preferably used in terms of easy control of the pore diameter and excellent durability. In particular, a polyamide separation functional layer obtained by polycondensation of a polyfunctional amine and a polyfunctional acid halide, an organic-inorganic hybrid functional layer, and the like are preferably used in terms of excellent separation performance of components in raw water. These separation functional layers can be formed by polycondensation of monomers on the porous support layer.

  For example, the separation functional layer can contain polyamide as a main component. Such a film is formed by interfacial polycondensation of a polyfunctional amine and a polyfunctional acid halide by a known method. For example, by applying a polyfunctional amine aqueous solution to the porous support layer, removing the excess amine aqueous solution with an air knife or the like, and then applying an organic solvent solution containing a polyfunctional acid halide, the polyamide separation functional layer Is obtained.

  Further, the constituent component of the separation functional layer is not limited to polyamide, and may be an organic-inorganic hybrid having Si element or the like.

  For any separation functional layer, the surface of the membrane may be hydrophilized with an alcohol-containing aqueous solution or an alkaline aqueous solution, for example, before use.

<Porous support layer>
The porous support layer is a layer that supports the separation functional layer, and is also referred to as a porous resin layer.

  Although the material used for a porous support layer and its shape are not specifically limited, For example, you may form on a board | substrate with porous resin. As the porous support layer, polysulfone, cellulose acetate, polyvinyl chloride, epoxy resin or a mixture and laminate of them is used, and polysulfone with high chemical, mechanical and thermal stability and easy to control pore size. Is preferably used.

  The porous support layer gives mechanical strength to the separation membrane, and does not have separation performance like a separation membrane for components having a small molecular size such as ions. The pore size and pore distribution of the porous support layer are not particularly limited. For example, the porous support layer may have uniform and fine pores, or the side on which the separation functional layer is formed. It may have a pore size distribution such that the diameter gradually increases from the surface to the other surface. In any case, the projected area equivalent circle diameter of the pores measured using an atomic force microscope or an electron microscope on the surface on the side where the separation functional layer is formed is 1 nm or more and 100 nm or less. preferable. Particularly in terms of interfacial polymerization reactivity and retention of the separation functional layer, the pores on the surface on the side where the separation functional layer is formed in the porous support layer preferably have a projected area equivalent circle diameter of 3 nm to 50 nm. .

  The thickness of the porous support layer is not particularly limited, but is preferably in the range of 20 μm to 500 μm, more preferably 30 μm to 300 μm, for reasons such as giving strength to the separation membrane.

  The form of the porous support layer can be observed with a scanning electron microscope, a transmission electron microscope, or an atomic force microscope. For example, when observing with a scanning electron microscope, after peeling off the porous support layer from the substrate, it is cut by the freeze cleaving method to obtain a sample for cross-sectional observation. The sample is thinly coated with platinum, platinum-palladium, or ruthenium tetrachloride, preferably ruthenium tetrachloride, and observed with a high-resolution field emission scanning electron microscope (UHR-FE-SEM) at an acceleration voltage of 3 kV to 6 kV. A Hitachi S-900 electron microscope or the like can be used as the high-resolution field emission scanning electron microscope. Based on the obtained electron micrograph, the film thickness of the porous support layer and the projected area equivalent circle diameter of the surface can be measured.

  The thickness and pore diameter of the porous support layer are average values, and the thickness of the porous support layer is measured at intervals of 20 μm in a direction perpendicular to the thickness direction by cross-sectional observation, and is an average value of 20 points. Moreover, a hole diameter is an average value of each projected area circle equivalent diameter measured about 200 holes.

  Next, a method for forming the porous support layer will be described. The porous support layer is formed by casting a solution of polysulfone in N, N-dimethylformamide (hereinafter referred to as DMF), for example, on a substrate to be described later, for example, a densely woven polyester cloth or non-woven cloth, to a certain thickness. And can be produced by wet coagulation in water.

  The porous support layer is “Office of Saleen Water Research and Development Progress Report” no. 359 (1968). In addition, in order to obtain a desired form, the polymer concentration, the temperature of the solvent, and the poor solvent can be adjusted.

  For example, a predetermined amount of polysulfone is dissolved in DMF to prepare a polysulfone resin solution having a predetermined concentration. Next, this polysulfone resin solution is applied to a substrate made of polyester cloth or nonwoven fabric to a substantially constant thickness, and after removing the surface solvent in the air for a certain period of time, the polysulfone is coagulated in the coagulation liquid. Can be obtained.

<Base material>
From the viewpoint of the strength and dimensional stability of the separation membrane body, the separation membrane body may have a substrate. As the base material, it is preferable to use a fibrous base material in terms of strength, unevenness forming ability and fluid permeability.

  As a base material, both a long fiber nonwoven fabric and a short fiber nonwoven fabric can be used preferably. In particular, since the long fiber nonwoven fabric has excellent film-forming properties, when the polymer solution is cast, the solution penetrates through the permeation, the porous support layer peels off, and Can suppress the film from becoming non-uniform due to fluffing of the substrate and the like, and the occurrence of defects such as pinholes. In addition, since the base material is made of a long-fiber non-woven fabric composed of thermoplastic continuous filaments, compared to short-fiber non-woven fabrics, it suppresses the occurrence of non-uniformity and film defects caused by fiber fluffing during casting of a polymer solution. be able to. Furthermore, since the separation membrane is tensioned in the film-forming direction when continuously formed, it is preferable to use a long-fiber nonwoven fabric excellent in dimensional stability as a base material.

  In the long-fiber nonwoven fabric, in terms of moldability and strength, it is preferable that the fibers in the surface layer on the side opposite to the porous support layer have a longitudinal orientation than the fibers in the surface layer on the porous support layer side. According to such a structure, not only a high effect of preventing membrane breakage by maintaining strength is realized, but also a laminate comprising a porous support layer and a substrate when imparting irregularities to the separation membrane The moldability is improved, and the uneven shape on the surface of the separation membrane is stabilized, which is preferable.

  More specifically, the fiber orientation degree in the surface layer on the side opposite to the porous support layer of the long-fiber nonwoven fabric is preferably 0 ° or more and 25 ° or less, and the fiber orientation in the surface layer on the porous support layer side. The degree of orientation difference with respect to the degree is preferably 10 ° or more and 90 ° or less.

  The separation membrane manufacturing process and the element manufacturing process include a heating process, but a phenomenon occurs in which the porous support layer or the separation functional layer contracts due to the heating. In particular, the shrinkage is remarkable in the width direction where no tension is applied in continuous film formation. Since shrinkage causes problems in dimensional stability and the like, a substrate having a small rate of thermal dimensional change is desired. In the nonwoven fabric, when the difference between the fiber orientation degree on the surface layer opposite to the porous support layer and the fiber orientation degree on the porous support layer side surface layer is 10 ° or more and 90 ° or less, the change in the width direction due to heat is suppressed. Can also be preferred.

  Here, the fiber orientation degree is an index indicating the direction of the fibers of the nonwoven fabric substrate constituting the porous support layer. Specifically, the fiber orientation degree is the film forming direction (MD) when performing continuous film formation, that is, the angle between the longitudinal direction of the nonwoven fabric substrate and the longitudinal direction of the fibers constituting the nonwoven fabric substrate. Average value. That is, if the longitudinal direction of the fiber is parallel to the film forming direction, the fiber orientation degree is 0 °. If the longitudinal direction of the fiber is perpendicular to the film forming direction, that is, if it is parallel to the width direction of the nonwoven fabric substrate, the degree of orientation of the fiber is 90 °. Accordingly, the closer to 0 ° the fiber orientation, the longer the orientation, and the closer to 90 °, the lateral orientation.

  The degree of fiber orientation is measured as follows. First, 10 small piece samples are randomly collected from the nonwoven fabric. Next, the surface of the sample is photographed at 100 to 1000 times with a scanning electron microscope. In the photographed image, 10 fibers are selected for each sample, and the angle of the fibers in the longitudinal direction when the longitudinal direction of the nonwoven fabric is 0 ° is measured. Here, the longitudinal direction of the nonwoven fabric refers to “Machine direction” at the time of manufacturing the nonwoven fabric. The longitudinal direction of the nonwoven fabric coincides with the film forming direction of the porous support layer. These directions coincide with the surrounding direction in the figure. The CD direction in the figure corresponds to “Cross direction” at the time of manufacturing the nonwoven fabric. In this way, the angle is measured for a total of 100 fibers per nonwoven fabric. The average value is calculated from the angles in the longitudinal direction for the 100 fibers thus measured. The value obtained by rounding off the first decimal place of the obtained average value is the fiber orientation degree.

  The thickness of the substrate is preferably in the range of 30 μm to 300 μm, or in the range of 50 μm to 250 μm.

(1-3) Permeation side channel material <Overview>
The permeate-side flow channel material of the present invention is composed of a sheet and a protrusion, and has an aperture on the surface of the sheet. The presence of the opening on the surface of the sheet makes the protrusion firmly fixed to the sheet, and the protrusion is less likely to be peeled off even in the process of cutting the permeate-side channel material during the manufacture of the separation membrane element. The process can be stabilized.

  As will be described later, the sheet has a dense weld portion, a coarse weld portion, and a non-weld portion non-woven fabric welded to the surface. That is, after the sheet is welded, protrusions are formed on the sheet surface.

  Moreover, the permeation | transmission side channel material is arrange | positioned at the permeation | transmission side surface 22 of the membrane leaf 4, as shown in FIG. At this time, whether the projections are in contact with the transmission side surface 22 or the sheet is in contact with the transmission side surface 22 depends on whether the membrane leaf 4 is wrapped or laminated. Since the sheet comes into contact with each other and eventually becomes the same state, there is no particular limitation. The details of the configuration of the permeate-side channel material are as follows.

<Permeate channel material>
In the separation membrane element, the sheet 13 constituting the permeate-side flow path member is preferably arranged such that the second direction (length direction of the separation membrane) coincides with the surrounding direction as shown in FIG. That is, in the separation membrane element of FIG. 8, the sheet 13 has a first direction (width direction of the separation membrane) parallel to the longitudinal direction of the water collecting pipe 6 and a second direction orthogonal to the longitudinal direction of the water collecting pipe 6. It is preferable to arrange | position.

  Moreover, the sheet | seat which comprises a permeation | transmission side channel material exists in the area | region which adhere | attaches the permeation | transmission side surfaces of a separation membrane. That is, it is preferable that the two separation membranes are bonded to each other with the sheet constituting the permeation side flow path member interposed therebetween, and the sheet exists between the separation membranes in at least a part of the bonded portion. In FIG. 9, the size of the sheet 13 constituting the permeate-side flow path material is the same as the size of the separation membrane, but actually, the sheet may be larger or the separation membrane may be larger. Good. When the separation membrane is larger, the sheet becomes a wall, so that the spread of the adhesive can be suppressed.

(Sheet)
The sheet is preferably a non-woven fabric from the viewpoint of impregnation control of the protrusions and handleability.

(Thickness H1 of the sheet constituting the permeate side channel material)
It is preferable that the thickness of the sheet | seat which comprises a permeation | transmission side channel material is 0.2 mm or less. This is because the sheet is preferably impregnated with an adhesive in order to seal between the permeation side surfaces of the two separation membranes. Further, as the sheet is made thinner, the protrusions described later become higher, the flow resistance as the permeate-side channel material decreases, and the element performance tends to improve.

(Porosity of the sheet constituting the permeate side channel material)
The porosity of the sheet 13 constituting the permeate side channel material is preferably 20% or more and 90% or less, and particularly preferably 45% or more and 80% or less. Here, the porosity means the ratio of the voids per unit volume of the substrate, and the weight when the substrate is dried is subtracted from the weight when pure water is included in the substrate having a predetermined apparent volume. The value obtained by dividing the obtained value by the apparent volume of the substrate is expressed as a percentage (%).

  When the porosity of the sheet 13 is 20% or more and 90% or less, the protrusions 3 can be impregnated and fixed, and a space through which water can pass can be easily secured in the sheet 13.

<Constituent components of protrusion>
The component constituting the protrusion is not limited to a specific substance, but a resin is preferably used. Specifically, in view of chemical resistance, ethylene vinyl acetate copolymer resin, polyolefin such as polyethylene and polypropylene, and polyolefin copolymer are preferable. In addition, the material of the permeate side channel material is urethane resin, epoxy resin, polyethersulfone, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polystyrene, styrene-acrylonitrile copolymer Polymer, styrene-butadiene-acrylonitrile copolymer, polyacetal, polymethyl methacrylate, methacryl-styrene copolymer, cellulose acetate, polycarbonate, polyethylene terephthalate, polybutadiene terephthalate and fluororesin (ethylene trifluoride chloride, polyvinylidene fluoride, tetrafluoride) Ethylene, ethylene tetrafluoride-hexafluoropropylene copolymer, ethylene tetrafluoride-perfluoroalkoxyethylene copolymer, ethylene tetrafluoride-ethylene copolymer Etc.) can also be selected polymers such as. These materials are used alone or as a mixture of two or more. In particular, since the thermoplastic resin is easy to mold, it is possible to form a permeate-side channel material having a uniform shape, and the sheet and the protrusion may be the same material or different materials.

<< Protrusions made of polypropylene >>
In addition, since the protrusion has the following configuration, the balance between pressure resistance and flexibility can be achieved, and driving stability can be improved. That is, the protrusion may include highly crystalline polypropylene and may satisfy the following requirements (a) and (b).
(A) Content of highly crystalline polypropylene is 20 to 95 weight% in the composition which comprises protrusion.
(B) The melting endotherm (ΔH) of the protrusion is 20 to 70 J / g.

  In this case, curling of the separation membrane on which the protrusion is formed can be suppressed by setting the content of the highly crystalline polypropylene to 95% by weight or less in the composition constituting the protrusion. Thereby, the handling property of the separation membrane is improved, and the permeability in the step of laminating the envelope membrane, which is one of the manufacturing steps of the separation membrane element, is remarkably improved. The content of the highly crystalline polypropylene is more preferably 85% by weight or less, and further preferably 75% by weight or less.

  On the other hand, when the content of the highly crystalline polypropylene is 20% by weight or more in the composition constituting the protrusions, not only the curling of the separation membrane is improved, but the separation membrane element of the present invention, for example, 2 MPa Even if the operation is performed under a pressurizing condition exceeding 1, it is possible to suppress the compressive deformation of the protrusions, and as a result, it is possible to suppress a decrease in the separation membrane element performance (particularly, the fresh water generation performance) and to exhibit stable performance. From the viewpoint of suppressing the amount of compressive deformation, the content of the highly crystalline polypropylene is more preferably 45% by weight or more, and further preferably 50% by weight.

  Examples of the highly crystalline polypropylene include a propylene homopolymer; a propylene random copolymer; a propylene block copolymer, and the like. These may be used alone or in admixture of two or more. The melting point of the highly crystalline polypropylene is preferably 140 ° C. or higher, and more preferably 150 ° C. or higher. The melting point is a value measured with a differential scanning calorimeter (DSC). For example, a sample is evaluated using a thermal analyzer such as a thermomechanical analyzer TMA / SS-6000 manufactured by Seiko Instruments Inc. under the conditions of probe: penetration probe, measurement load: 10 g, temperature increase rate: 5 ° C./min. The melting point can be measured.

  Furthermore, the melt flow rate (MFR) of the highly crystalline polypropylene is preferably 10 to 2000 g / 10 min. By setting the MFR in such a range, it is easy to melt-mold the permeate-side channel material. It is also possible to set the melt molding temperature low. As a result, it is possible to suppress damage to the separation membrane body due to heat and degradation of the separation membrane performance during melt molding, and to adhere to the permeate side surface of the separation membrane body. Property is improved. The MFR of the highly crystalline polypropylene is more preferably 30 to 1800 g / 10 min, and further preferably 50 to 1500 g / min. The MFR is a value measured under conditions of 230 ° C. and a load of 2.16 kg according to JIS-K7200 (1999).

  The melting endotherm (ΔH) of the protrusion is preferably 20 to 70 J / g. Since the melting endotherm (ΔH) is 20 to 70 J / g, the sheet-curling and the stickiness of the protrusions are suppressed while suppressing the sheet curling.

  The ΔH of the protrusion is more preferably 25 to 65 J / g, and further preferably 30 to 60 J / g. The melting endotherm is a numerical value measured with a differential scanning calorimeter (DSC). For example, measurement was performed using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., and 10 mg of a sample was heated from 20 ° C. to 220 ° C. at a temperature rising rate of 10 ° C./min and held at 220 ° C. for 10 minutes. Thereafter, in the measurement of lowering the temperature to 20 ° C. at a temperature lowering rate of 10 ° C./min, the calorific value based on crystallization observed when the temperature is lowered can be obtained.

  Further, the composition constituting the protrusion preferably contains a low crystalline α-olefin polymer, and the content thereof is preferably 5 to 60% by weight in the composition constituting the protrusion.

  The low crystallinity α-olefin polymer of the present invention is an amorphous or low crystallinity α-olefin polymer, for example, low crystalline polypropylene such as atactic polypropylene or isotactic polypropylene having low stereoregularity. An ethylene / α-olefin copolymer selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms (as the α-olefin having 3 to 20 carbon atoms, linear and branched α-olefins); Specifically, examples of the linear α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene 1-nonadecene, 1-eicosene and the like, and examples of the branched α-olefin include 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl- 1-hexene, 2,2,4-trimethyl-1-pentene and the like); (B-3) Commercially available propylene such as “Tuffmer” manufactured by Mitsui Chemicals, Inc. and “Tufselen” manufactured by Sumitomo Chemical Co., Ltd. -An olefin copolymer etc. can be illustrated. In the present invention, one or more of these can be used. Among them, the low crystalline α-olefin polymer (B) includes low crystalline polypropylene and propylene / olefin copolymer from the viewpoints of good compatibility with high crystalline polypropylene, versatility, and curling improvement effect of the separation membrane. A polymer is more preferred.

  In the present embodiment, the content of the low crystalline α-olefin polymer (B) is preferably 5 to 60% by weight with respect to the composition constituting the protrusions. By setting the content of the low crystalline α-olefin polymer to 5% by weight or more, flexibility can be imparted to the protrusions, and the crystallization speed of the high crystalline polypropylene can be delayed. Curling can be suppressed. On the other hand, when the content of the low crystalline α-olefin polymer exceeds 60% by weight, the curl of the separation membrane can be greatly improved, but the flexibility of the protrusions is remarkably increased, for example, under pressure conditions exceeding 2 MPa. When operated, the amount of compressive deformation of the protrusions increases, and as a result, the separation membrane element performance (especially water production performance) is greatly reduced due to the blockage of the flow path. The content of the low crystalline α-olefin polymer is more preferably from 10 to 55% by weight, and further preferably from 15 to 50% by weight, from the viewpoint of the flexibility of the protrusions and the compressive deformability under pressure. preferable.

  In this embodiment, it is preferable that the tensile elongation of the protrusions fixed to the permeation side surface of the separation membrane body is 5% or more. When the tensile elongation is 5% or more, even if the separation membrane is rolled or wound on a winder, the protrusion can be prevented from being damaged or broken, and a high-quality separation membrane can be obtained. Handleability is improved in the manufacturing process. The tensile elongation is more preferably 7% or more, still more preferably 10% or more. In addition, the higher the tensile elongation, the higher the energy required for fracture, which is preferable from the viewpoint of toughness. However, if the tensile elongation is excessively high, the amount of deformation under a constant stress increases, so 300% or less is preferable. 200% or less is more preferable.

  In the present embodiment, the tensile elastic modulus of the protrusion is preferably 0.2 to 2.0 GPa. By setting the tensile elastic modulus to 0.2 GPa or more, even when the separation membrane element is operated under a pressure condition exceeding 2.0 MPa, the amount of compressive deformation of the protrusions can be suppressed. Reduction can be suppressed. The tensile elastic modulus is more preferably 0.25 GPa or more, and further preferably 0.30 GPa or more. The higher the tensile elastic modulus, the more the amount of compressive deformation of the protrusions during the pressurizing operation can be suppressed, but it is difficult to substantially achieve 2.0 GPa or more.

<Shape and arrangement of protrusions>
<< Overview >>
A tricot that has been widely used in the past is a knitted fabric, and is composed of three-dimensionally intersecting yarns. That is, the tricot has a two-dimensionally continuous structure. When such a tricot is applied as a permeate-side channel material, the height of the channel is smaller than the thickness of the tricot. That is, it is a structure with many ratios which do not become a groove.

  On the other hand, as an example of the configuration of the present invention, a protrusion 3 shown in FIG. Therefore, since the height (that is, the thickness) of the protrusion 3 of the present embodiment is utilized as the height of the groove of the flow path, the tricot having the same thickness as the flow path material of the present embodiment as the sheet is thinner and the protrusion is higher. Since the flow paths (grooves between the protrusions 3 and the surface opening portions in the sheet 13) are wider than when the is applied, the flow resistance tends to be smaller.

  In the form shown in each figure, a plurality of discontinuous projections 3 are fixed on one sheet 13. “Discontinuous” is a state in which a plurality of flow path members are provided at intervals. That is, when one protrusion 3 is peeled from the sheet 13, a plurality of protrusions 3 separated from each other are obtained. On the other hand, members such as nets, tricots, and films exhibit a continuous and integral shape even when the flow path is separated from the sheet 13.

  By providing a plurality of discontinuous protrusions 3, the separation membrane 2 can suppress a pressure loss when it is incorporated in a separation membrane element 100 described later. As an example of such a configuration, in FIG. 2, the protrusions 3 are formed discontinuously only in the first direction (the width direction of the sheet 13), and in FIG. 3, the first direction (the width direction of the sheet 13) and the second direction. It is formed discontinuously in any direction (length direction of the separation membrane).

  2 and 3, the permeation side flow path 5 is formed in the space between the adjacent protrusions 3.

  In the form shown in FIG. 2, the permeate-side channel material 31 is provided discontinuously in the first direction and is provided so as to continue from one end to the other end of the sheet 13 in the second direction. That is, when the sheet 13 is incorporated into the separation membrane element as shown in FIG. 5, the protrusions 3 are arranged so as to continue from the inner end to the outer end of the sheet 13 in the surrounding direction. The inner side in the winding direction is the side close to the water collection pipe 6 in the separation membrane, and the outer side in the winding direction is the side far from the water collection pipe 6 in the separation membrane.

The passage material is “continuous in the second direction” means that the passage material is provided without interruption as shown in FIG. 2 and the passage material is interrupted as shown in FIG. It includes both cases where the channel material is substantially continuous. In the “substantially continuous” form, preferably, as shown in FIG. 3, the distance e between the flow path members in the second direction (that is, the length of the discontinuous portion in the flow path material) is 5 mm or less. Satisfy that. In particular, the distance e is more preferably 1 mm or less, and further preferably 0.5 mm or less. In addition, the total value of the intervals e included from the beginning to the end of the line of flow path materials arranged in the second direction is preferably 100 mm or less, more preferably 30 mm or less, and more preferably 3 mm or less. Further preferred. In the form of FIG. 2, the interval e is 0 (zero).
When the protrusions 3 are provided without interruption in the second direction as shown in FIG. 2, membrane drop is suppressed during pressure filtration. Membrane sagging is that the membrane falls into the channel and narrows the channel.

  In FIG. 3, the protrusions 3 are discontinuously provided not only in the first direction but also in the second direction. That is, the protrusions 3 are provided at intervals in the length direction. However, as described above, the protrusion 3 is substantially continuous in the second direction, so that the film sagging is suppressed. However, by providing the discontinuous protrusions 3 in the two directions as described above, the contact area between the flow path material and the fluid is reduced, so that the pressure loss is reduced. In other words, this form is a configuration in which the permeation-side flow path 5 includes a branch point. That is, in the configuration of FIG. 3, the permeating fluid is divided by the protrusions 3 and the sheet 13 while flowing through the permeation-side flow path 5, and can further merge downstream. As described above, in FIG. 2, the protrusion 3 is provided so as to continue from one end to the other end of the sheet 13 in the second direction. In FIG. 3, the protrusion 3 is divided into a plurality of portions in the second direction, but these plurality of portions are provided so as to be arranged from one end to the other end of the sheet 13.

  The passage material is “provided from one end of the sheet to the other end” means that the protrusion 3 is provided to the edge of the sheet 13 and that there is a region where the protrusion 3 is not provided in the vicinity of the edge. Including both. In other words, the protrusions 3 need only be distributed in the second direction to such an extent that a passage on the transmission side can be formed, and there may be a portion of the sheet 13 where the protrusions 3 are not provided. For example, the protrusion 3 does not need to be provided on a portion (in other words, a contact portion) bonded to the separation membrane on the surface on the transmission side.

<< Protrusion dimensions >>
2 to 4, a to f indicate the following values.

a: Length of the separation membrane 2 b: Distance between the projections 3 in the width direction of the separation membrane 2 c: Height of the projections (height difference between the projections 3 and the surface 22 on the transmission side of the sheet)
d: Width of the protrusion 3 e: Distance between the protrusions in the length direction of the separation membrane 2 f: Length of the protrusion 3 For measurement of the values a, b, c, d, e, f, for example, commercially available shape measurement A system or a microscope can be used. Each value is obtained by performing measurement at 30 or more locations on one separation membrane, and calculating an average value by dividing the sum of these values by the number of measurement total locations. Thus, each value obtained as a result of the measurement at at least 30 locations should satisfy the range described below.

(Separation membrane length a)
The length a is a distance from one end of the separation membrane 2 to the other end in the second direction (length direction of the separation membrane). When this distance is not constant, the length a can be obtained by measuring this distance at 30 or more positions in one separation membrane 2 and obtaining an average value.

(Distance b of the protrusions 3 in the width direction of the separation membrane)
The interval b between the adjacent projections 3 in the first direction (the width direction of the separation membrane) corresponds to the width of the permeation side flow path 5. When the width of one permeation side flow path 5 is not constant in one cross section, that is, when the side surfaces of two adjacent protrusions 3 are not parallel, the maximum width of one permeation side flow path 5 within one cross section The average value of the value and the minimum value is measured, and the average value is calculated. As shown in FIG. 4, in the cross section perpendicular to the second direction, when the protrusion 3 has a trapezoidal shape with a thin top and a thick bottom, first, the distance between the upper parts of the two adjacent protrusions 3 and the distance between the lower parts Measure and calculate the average value. The distance between two adjacent protrusions 3 is measured in any 30 or more cross sections, and an average value is calculated in each cross section. And the space | interval b is calculated by calculating further the arithmetic mean value of the average value obtained in this way.

  As the distance b increases, the pressure loss decreases, but the film falls easily. Conversely, the smaller the distance b, the less likely the film will drop, but the greater the pressure loss. Considering the pressure loss, the interval b is preferably 0.05 mm or more, 0.2 mm or more, or 0.3 mm or more. Further, in terms of suppressing film sagging, the interval b is preferably 5 mm or less, 3 mm or less, 2 mm or less, or 0.8 mm or less.

  These upper and lower limits can be combined arbitrarily. For example, the interval b is preferably 0.05 mm or more and 5 mm or less, and within this range, the pressure loss can be reduced while suppressing the film sagging. The distance b is more preferably 0.05 mm or more and 3 mm or less, 0.2 mm or more and 2 mm or less, and further preferably 0.3 mm or more and 0.8 mm or less.

(Protrusion height c)
The height c is a difference in height between the protrusion and the surface of the sheet 13. As shown in FIG. 4, the height c is a difference in height between the highest portion of the protrusion 3 and the transmission side surface of the sheet 13 in a cross section perpendicular to the second direction. That is, as the height of the protrusion, the thickness of the portion impregnated in the base material is not considered. The height c is a value obtained by measuring and averaging the heights of 30 or more protrusions 3. The height c of the protrusion may be obtained by observing the cross section of the flow path material in the same plane, or may be obtained by observing the cross sections of the flow path material in a plurality of planes.

  The height c can be appropriately selected according to the use conditions and purpose of the separation membrane element, but may be set as follows, for example.

  The larger the height c, the smaller the flow resistance. Therefore, the height c is preferably 0.10 mm or more, 0.15 mm or more, or 0.20 mm or more. On the other hand, the smaller the height c, the larger the number of membranes filled per separation membrane element. Therefore, the height c is preferably 0.45 mm or less. These upper and lower limits can be combined. For example, the height c is preferably 0.10 mm or more and 0.45 mm or less, preferably 0.15 mm or more and 0.45 mm or less, and 0.20 mm or more. More preferably, it is 0.45 mm or less.

(Protrusion sticking to the permeation side of the separation membrane)
The protrusion described above may be directly fixed to the permeation side of the separation membrane. In this case, since the sheet is unnecessary, the protrusion can be increased by the thickness of the sheet, and the permeation side flow path can be widened to further improve the water-forming property of the element.

(Width d of the channel material)
The width d of the protrusion 3 is measured as follows. First, an average value of the maximum width and the minimum width of one protrusion 3 is calculated in one cross section perpendicular to the first direction (the width direction of the separation membrane). That is, in the projection 3 with a thin upper part and a thick lower part as shown in FIG. 4, the width of the lower part and the upper part of the channel material are measured, and the average value is calculated. By calculating such an average value in at least 30 cross-sections and calculating the arithmetic average thereof, the width d per film can be calculated.

  The width d of the protrusion 3 is preferably 0.2 mm or more, and more preferably 0.3 mm or more. Since the width d is 0.2 mm or more, the shape of the flow path material can be maintained even when pressure is applied to the protrusion 3 or the sheet 13 during operation of the separation membrane element, and the permeate-side flow path is stably formed. Is done. The width d is preferably 2 mm or less, and more preferably 1.5 mm or less. When the width d is 2 mm or less, a sufficient flow path on the permeate side can be secured.

  When the width d of the protrusion 3 is wider than the interval b of the protrusion 3 in the second direction, the pressure applied to the flow path material can be dispersed.

  The protrusion 3 is formed such that its length is larger than its width. Such a long protrusion 3 is also referred to as a “wall-like object”.

(Distance e between protrusions in the length direction of the separation membrane)
The distance e between the protrusions 3 in the second direction (the length direction of the separation membrane) is the shortest distance between adjacent protrusions 3 in the second direction (the length direction of the separation film). As shown in FIG. 2, the protrusion 3 is provided continuously from one end to the other end of the separation membrane 2 in the second direction (in the separation membrane element, from the inner end to the outer end in the surrounding direction). In this case, the interval e is 0 mm. As shown in FIG. 3, when the protrusion 3 is interrupted in the second direction, the interval e is preferably 5 mm or less, more preferably 1 mm or less, and further preferably 0.5 mm or less. When the distance e is within the above range, the mechanical load on the film is small even when the film is dropped, and the pressure loss due to the blockage of the flow path can be relatively small. In addition, the minimum of the space | interval e is 0 mm.

(Projection length f)
The length f of the protrusion 3 is the length of the protrusion 3 in the length direction of the separation membrane 2 (that is, the second direction). The length f is obtained by measuring the length of 30 or more protrusions 3 in one separation membrane 2 and calculating an average value thereof. The length f of the protrusion 3 may be equal to or less than the length a of the separation membrane. When the length f of the protrusion 3 is equal to the length a of the separation membrane, it means that the protrusion 3 is continuously provided from the inner end to the outer end in the winding direction of the separation membrane 2. The length f is preferably 10 mm or more, more preferably 20 mm or more. Since the length f is 10 mm or more, the flow path is secured even under pressure.

(Shape of protrusion)
The shape of the protrusion 3 is not particularly limited, but a shape that reduces the flow resistance of the flow path and stabilizes the flow path when permeated can be selected. In these respects, in any cross section perpendicular to the surface direction of the separation membrane, the shape of the protrusion 3 may be a straight column shape, a trapezoidal shape, a curved column shape, or a combination thereof.

  When the cross-sectional shape of the protrusion 3 is trapezoidal, if the difference between the length of the upper base and the length of the lower base is too large, membrane drop during pressure filtration is likely to occur at the membrane in contact with the smaller one. For example, when the upper base of the channel material is shorter than the lower base, the upper width of the channel between them is wider than the lower width. Therefore, the upper film tends to drop downward. Therefore, in order to suppress such a drop, the ratio of the length of the upper base to the length of the lower base of the flow path material is preferably 0.6 or more and 1.4 or less, and is 0.8 or more and 1.2 or less. Further preferred.

  From the viewpoint of reducing flow resistance, the shape of the protrusion 3 is preferably a straight column shape perpendicular to the later-described separation membrane surface. Further, the protrusion 3 may be formed so that the width becomes smaller at a higher portion, or conversely, the protrusion 3 may be formed at a height from the surface of the separation membrane. However, it may be formed to have the same width.

  However, the upper side may be rounded in the cross section of the protrusion 3 as long as the flow path material is not significantly crushed during pressure filtration.

  The protrusion 3 can be formed of a thermoplastic resin. If the projection 3 is a thermoplastic resin, the shape of the flow path material can be adjusted freely so that the required separation characteristics and permeation performance conditions can be satisfied by changing the processing temperature and the type of thermoplastic resin to be selected. can do.

  Further, the shape of the projection 3 in the planar direction of the separation membrane may be linear as a whole as shown in FIGS. 2 and 3, and other shapes are, for example, curved, sawtooth, and wavy. May be. Further, in these shapes, the protrusion 3 may be a broken line or a dot. From the viewpoint of reducing the flow resistance, a dot shape or a broken line shape is preferable. However, since the flow path material is interrupted, the number of places where film sagging occurs during pressure filtration increases.

  Moreover, when the shape in the planar direction of the sheet | seat 13 of the processus | protrusion 3 is linear shape, the adjacent flow-path material may be arrange | positioned substantially parallel mutually. “Arranged substantially in parallel” means, for example, that the channel material does not intersect on the separation membrane, the angle formed by the longitudinal direction of two adjacent channel materials is 0 ° or more and 30 ° or less, It includes that the angle is from 0 ° to 15 °, and that the angle is from 0 ° to 5 °.

  The angle formed by the longitudinal direction of the protrusion 3 and the longitudinal direction of the water collecting pipe 6 is preferably 60 ° or more and 120 ° or less, more preferably 75 ° or more and 105 ° or less, and 85 ° or more and 95 °. More preferably, it is as follows. When the angle formed by the longitudinal direction of the flow path material and the longitudinal direction of the water collecting pipe is within the above range, the permeated water is efficiently collected in the water collecting pipe.

  In order to stably form the flow path, it is preferable that the separation membrane can be prevented from dropping when the separation membrane is pressurized in the separation membrane element. For this purpose, it is preferable that the contact area between the separation membrane and the channel material is large, that is, the area of the channel material relative to the area of the separation membrane (projected area of the channel material with respect to the membrane surface of the separation membrane) is large. On the other hand, in order to reduce pressure loss, it is preferable that the cross-sectional area of a flow path is wide. In order to ensure a large cross-sectional area of the flow path while ensuring a large contact area between the separation membrane and the flow path material perpendicular to the longitudinal direction of the flow path, The shape is preferably a concave lens. Further, the protrusion 3 may have a straight column shape having no change in width in the cross-sectional shape in the direction perpendicular to the winding direction. In addition, the protrusion 3 has a trapezoidal wall-like object having a change in width, an elliptical column, a cross-sectional shape in a direction perpendicular to the surrounding direction, as long as the separation membrane performance is not affected. The shape may be an elliptical cone, a quadrangular pyramid, or a hemisphere.

  The shape of the protrusion 3 is not limited to the shape shown in FIGS. When the flow path material is arranged by fixing a molten material to the sheet 13 as in, for example, a hot melt method, the required separation can be achieved by changing the processing temperature or the type of hot melt resin to be selected. The shape of the protrusion 3 can be freely adjusted so as to satisfy the conditions of characteristics and transmission performance.

  In FIG. 2, the planar shape of the protrusion 3 is linear in the length direction. However, the protrusion 3 can be changed to another shape as long as it is convex with respect to the surface of the separation membrane 2 and does not impair the desired effect as the separation membrane element. That is, the shape of the channel material (projection) in the planar direction may be a curved shape, a wavy shape, or the like. A plurality of flow path materials (projections) included in one separation membrane may be formed so that at least one of the width and the length is different from each other.

<Protrusion group and separation protrusion>
In the sheet shown in FIG. 7, a plurality of resin bodies are fixed as protrusions on the surface on the transmission side. The protrusion group 31 is composed of a plurality of resin bodies and the separation protrusions 32, and the separation protrusions are arranged outside the longitudinal end of the water collecting pipe of at least one of the protrusion groups.

  The protrusion group 31 is a group that substantially forms a permeate-side flow path.

  The separation protrusion 32 is a protrusion disposed outside the protrusion group 31 in the width direction of the separation membrane element, and in the element manufacturing process, to the outside of the leaf adhesive applied to the outside of the protrusion group. It regulates the spread of By disposing the separating protrusions in this way, it is possible to regulate the spread of the leaf adhesive at the time of winding, so that it is possible to sufficiently seal even if the application amount is small. Furthermore, in order to prevent the leaf adhesive from spreading into the element, it is preferable that the projection group and the separation-side projection are continuously provided in the surrounding direction as shown in FIG.

  A plurality of the spaced protrusions 32 and the protrusion collectives 31 may be arranged, or may be singular. The width, height, and shape of the separation protrusions may be the same as or different from the protrusions in the protrusion group of the protrusion group.

  The width of the protrusions in the protrusion group is preferably 0.05 mm or more and 5 mm or less. The intensity | strength suitable as a protrusion can be acquired because the width | variety of a protrusion is 0.05 mm or more. When the width of the width protrusion is 5 mm or less, it becomes easy to secure a sufficient width for the groove serving as the flow path. As a result, the flow resistance on the permeate side can be kept low. Moreover, it is preferable that the width | variety of a protrusion is 0.2 mm or more or 0.4 mm or more.

  It is preferable that the protrusion interval 51 in the protrusion group is 0.1 mm or more and 1.0 mm or less. If it is less than 0.1 mm, the effect as a channel material is not exhibited and a sufficient amount of water is not obtained, and if it exceeds 1.0 mm, the channel is crushed due to falling of the membrane, and a sufficient amount of water is not obtained. The protrusion interval 51 in the protrusion group is the shortest distance between adjacent protrusions in the second direction (the length direction of the separation membrane).

  It is preferable that the distance 51 in the longitudinal direction of the water tube between the projection group and the separation projection is 10 mm or more and 50 mm or less. When making an element, an adhesive is applied between the projections and the separation protrusions at the winding stage, but the presence of the separation protrusions prevents adhesive leakage, and a small amount of adhesive provides a sufficient adhesion effect. Can be obtained. If it is less than 10 mm, sufficient adhesive force cannot be exhibited during winding, and if it exceeds 50 mm, an area where the adhesive is not applied after forming the separation membrane element, that is, an area where pressure filtration functions effectively (effective membrane) Area) is not secured, and a sufficient amount of fresh water cannot be obtained.

  The height of the separation protrusion and the height of the protrusion group are preferably 0.1 mm or more and 1.0 mm or less. If the thickness is less than 0.1 mm, the flow path becomes narrow and a sufficient amount of water cannot be obtained. If the thickness exceeds 1.0 mm, the number of membranes filled in the element decreases, and a sufficient amount of water is not obtained. The height of the separation protrusion and the height of the protrusion group may be the same or different.

(1-3) Protrusion (permeation side channel material)
<Overview>
The permeation side surface of the separation membrane main body has a composition different from that of the base material, and is adhered to the side opposite to the separation functional layer in the thickness direction of the base material so as to form a permeation side flow path. Protrusions are provided. “Provided so as to form a permeate-side flow path” means that when the separation membrane is incorporated into a separation membrane element described later, the permeated fluid that has permeated the separation membrane main body can reach the water collecting pipe. It means that an object is formed. The details of the configuration of the protrusion are as follows.

<Constituent components of protrusion>
The protrusion 3 is preferably formed of a material different from that of the separation membrane body 2. The different material means a material having a composition different from that of the material used in the separation membrane body 2. In particular, the composition of the protrusion 3 is preferably different from the composition of the surface of the separation membrane body 2 on which the protrusion 3 is formed, and may be different from the composition of any layer forming the separation membrane body 2. preferable.

  Although it does not specifically limit as a material which comprises, Resin is used preferably. Specifically, from the viewpoint of chemical resistance, ethylene vinyl acetate copolymer resins, polyolefins such as polyethylene and polypropylene, and olefin copolymers are preferable, and polymers such as urethane resins and epoxy resins can also be selected. Or it can use as a mixture which consists of two or more types. In particular, since a thermoplastic resin is easy to mold, a projection having a uniform shape can be formed.

[2. Separation membrane element)
(2-1) Overview As shown in FIG. 6, the separation membrane element 100 includes the water collecting pipe 6 and any one of the above-described configurations, and includes the separation membrane 1 wound around the water collecting pipe 6. The separation membrane element 100 further includes a member such as an end plate (not shown).

(2-2) Separation membrane <Overview>
The separation membrane 1 is wound around the water collecting pipe 6 and is arranged so that the width direction is along the longitudinal direction of the water collecting pipe 6. As a result, the separation membrane 1 is disposed such that the surrounding direction is along the surrounding direction.

  Accordingly, the protrusions 3 that are wall-like objects are discontinuously arranged at least in the longitudinal direction of the water collecting pipe 6 on the permeation side surface 22 of the separation membrane 1. That is, the flow path 5 is formed to be continuous from the outer end to the inner end of the separation membrane in the surrounding direction. As a result, the permeated water can easily reach the central pipe, that is, the flow resistance is reduced, so that a large amount of fresh water is obtained.

  The “inner side in the surrounding direction” and “outer side in the surrounding direction” are as shown in FIG. That is, the “inner end portion in the surrounding direction” and the “outer end portion in the surrounding direction” correspond to the end portion closer to the water collecting pipe 6 and the far end portion in the separation membrane 1, respectively.

  As described above, since the protrusion does not need to reach the edge of the separation membrane, for example, at the outer end portion of the envelope-like membrane in the winding direction and at the end portion of the envelope-like membrane in the longitudinal direction of the water collecting tube The thing does not need to be provided.

<Membrane leaf and envelope membrane>
As shown in FIG. 1, the separation membrane 1 forms a membrane leaf 4 (sometimes simply referred to as “leaf” in this document). In the leaf 4, the separation membrane 1 is disposed so that the supply-side surface 21 faces the supply-side surface 71 of another separation membrane 7 with a supply-side flow path material (not shown) interposed therebetween. In the separation membrane leaf 4, a supply-side flow path is formed between the supply-side surfaces of the separation membranes facing each other.

  In addition, in one leaf 4, the space between the supply-side surfaces of the separation membrane 1 facing each other is closed by folding or sealing at the inner end portion in the winding direction (the portion indicated by the alternate long and short dash line).

  When the supply side surface of the separation membrane is sealed instead of being folded, bending at the end of the separation membrane hardly occurs. By suppressing the occurrence of bending in the vicinity of the crease, the generation of voids between the separation membranes when wound and the occurrence of leakage due to the voids are suppressed. When the separation membrane leaf is formed by folding, the longer the leaf (that is, the longer the original separation membrane), the longer the time required for folding the separation membrane. However, by sealing the supply side surface of the separation membrane instead of folding, an increase in manufacturing time can be suppressed even if the leaf is long.

  As shown in FIG. 1, a plurality of membrane leaves 4 are stacked. By superposing the membrane leaf 4, the separation membrane 1 and the separation membrane 7 of the other membrane leaf facing the permeation side surface 22 of the separation membrane 1 form a separation membrane pair 8. The separation membrane pair is also called an envelope membrane. In the envelope-shaped membrane, between the opposite permeate side surfaces, in the rectangular shape of the separation membrane, only one side inside the winding direction is opened so that the permeate flows to the water collecting pipe 6, and the other three sides are sealed. (Indicated by a two-dot chain line in the figure). The permeate is isolated from the raw water by this envelope membrane.

  As the form of the sealing portion on the surface on the transmission side, there are adhesion by a resin such as an adhesive (including hot melt), fusion by heating or laser, sealing by sandwiching a rubber sheet, etc. Can be mentioned. Sealing by adhesion is particularly preferable because it is the simplest and most effective. These techniques may also be applied to sealing the supply side surface. However, the sealing method may be the same or different between the transmission side surface and the supply side surface.

  As described above, since the supply side surface of the separation membrane is sealed rather than folded, bending at the end of the separation membrane hardly occurs. As a result, the occurrence of leak is suppressed and the recovery rate of the envelope-like film is improved. The recovery rate of the envelope-like film is obtained as follows. That is, an air leak test of the separation membrane element is performed in water, and the number of envelope-shaped membranes in which the leak has occurred is counted. Based on the count result, the ratio of (number of envelope films in which air leak has occurred / number of envelope films used for evaluation) is calculated as the recovery rate of the envelope film.

  A specific air leak test method is as follows. The end of the central pipe of the separation membrane element is sealed, and air is injected from the other end. The injected air passes through the holes of the water collection pipe and reaches the permeation side of the separation membrane. However, as described above, the separation membrane is not sufficiently folded and the surface on the permeation side is bent near the crease. When air gaps exist in the sealed portion, air moves to the separation membrane supply side. Then, air leaks into the water from the end of the separation membrane element, that is, from between the surfaces on the supply side. The air leak at this time can be confirmed as the generation of bubbles.

  In the separation membrane leaf and the envelope membrane, the separation membranes facing each other (separation membranes 1 and 7 in FIG. 1) may have the same configuration or different configurations. That is, in the separation membrane element, it is only necessary that the above-mentioned projection is provided on at least one of the two permeate-side surfaces facing each other, so that the separation membrane having the projection and the separation membrane not having the projection are alternately arranged. It may be piled up. However, for convenience of explanation, in the separation membrane element and the explanation related thereto, the “separation membrane” includes a separation membrane that does not have protrusions (for example, a membrane having the same configuration as the separation membrane main body).

  The separation membranes facing each other on the permeate side surface or the supply side surface may be two different separation membranes, or one membrane folded.

(2-3) Structure around the water collecting pipe The separation membrane element preferably includes a sheet having a gap wound around the water collecting pipe 2. As the sheet, like the tricot and the above-described base material, a member on a flat membrane having a void is preferable. In this sheet, the adhesive applied to the water collecting pipe 2 at the time of winding of the second party side element is difficult to flow, leading to suppression of leakage, and further, the flow path around the water collecting pipe is stably secured. In addition, what is necessary is just to wind the sheet | seat which has a space | gap longer than the circumference of a water collection pipe | tube.

(2-4) Supply side channel (channel material)
The separation membrane element 100 includes a channel material (not shown) having a projected area ratio with respect to the separation membrane 1 exceeding 0 and less than 1 between the surfaces on the supply side of the overlapping separation membranes. The projected area ratio of the supply-side channel material is preferably 0.03 or more and 0.50 or less, more preferably 0.10 or more and 0.40 or less, and particularly preferably 0.15 or more and 0.35 or less. . When the projected area ratio is 0.03 or more and 0.50 or less, the flow resistance can be suppressed to be relatively small. The projected area ratio refers to the projected area obtained when the separation membrane and the supply-side channel material are cut out at 5 cm × 5 cm, and the supply-side channel material is projected onto a plane parallel to the surface direction of the separation membrane. Divided value.

  As will be described later, the height of the supply-side channel material is preferably more than 0.5 mm and not more than 2.0 mm, more preferably not less than 0.6 mm and not more than 1.0 mm, in consideration of the balance of each performance and operation cost.

  The shape of the supply-side channel material is not particularly limited, and may have a continuous shape or a discontinuous shape. Examples of the channel material having a continuous shape include members such as a film and a net. Here, the continuous shape means that it is continuous over the entire range of the flow path material. The continuous shape may include a portion where a part of the flow path material is discontinuous to such an extent that a problem such as a decrease in the amount of water produced does not occur. The definition of “discontinuity” is as described for the passage-side channel material. The material of the supply side channel material is not particularly limited, and may be the same material as the separation membrane or a different material.

(2-5) Water Collection Pipe The water collection pipe 6 is not particularly limited as long as it is configured so that permeated water flows therethrough. As the water collecting pipe 6, for example, a cylindrical member having a side surface provided with a plurality of holes is used.

(2-6) End Plate As shown in FIG. 6, the separation membrane element 100 includes end plates 81 and 82 attached to both ends of the wound body of the separation membrane 1 in the longitudinal direction of the water collecting pipe 6. The end plate 81 includes a raw water hole 83 formed to allow raw water to pass therethrough and a center hole 84 formed to allow permeated water to pass therethrough. Similarly, the end plate 82 also forms a raw water hole 85 formed through which raw water can pass. , And a central hole 86 formed to allow permeate to pass therethrough.

  In FIG. 6, the shape of the end plate 81 and the shape of the end plate 82 are the same, but in one element, the shapes of the two end plates may be different from each other. In FIG. 6, the end plate 81 is disposed on the upstream side, and the end plate 82 is disposed on the downstream side.

  When a plurality of separation membrane elements 100 are used in a state where they are connected in series, the raw water is supplied to the separation membrane element located at the uppermost stream in the raw water supply direction via the raw water holes 83. In the most upstream separation membrane element, the hole 84 is not provided or blocked in the end plate located on the upstream side. The supplied raw water is divided into permeated water and concentrated water while passing through the wound body.

  The concentrated water passes through the raw water holes 85 in the downstream end plate, and further passes through the raw water holes 83 in the downstream element, and is similarly separated in the downstream element.

  The permeated water passes through the water collecting pipe 6 in the element, and further passes through the center hole 86 of the downstream end plate of the element and the center hole 84 of the upstream end plate of the next element, and then passes through the water collecting pipe 6 of the next element. Flow into. Eventually, the permeate is collected through the central hole 86 in the downstream end plate of the most downstream element.

[3. Method for manufacturing separation membrane element]
(3-1) Manufacture of separation membrane body The manufacturing method of the separation membrane body has been described above, but it is summarized as follows.

  The resin is dissolved in a good solvent, and the resulting resin solution is cast on a substrate and immersed in pure water to combine the porous support layer and the substrate. Thereafter, as described above, a separation functional layer is formed on the porous support layer. Furthermore, chemical treatment such as chlorine, acid, alkali, nitrous acid, etc. is performed to enhance separation performance and permeation performance as necessary, and the monomer is washed to produce a continuous sheet of the separation membrane body.

(3-2) Arrangement of Protrusions (Permeation Side Channel Material) The method for manufacturing a separation membrane includes a step of providing discontinuous projections on the permeation side surface of the separation membrane main body. This step may be performed at any time during the manufacture of the separation membrane. For example, the protrusion may be provided before the porous support layer is formed on the base material, or after the porous support layer is provided and before the separation functional layer is formed. Alternatively, after the separation functional layer is formed, it may be performed before or after the above-described chemical treatment is performed.

  The method for arranging the protrusions includes, for example, a step of placing a soft material on the separation membrane and a step of curing it. Specifically, ultraviolet curable resin, chemical polymerization, hot melt, drying, or the like is used for the arrangement of the protrusions. In particular, hot melt is preferably used. Specifically, a step of softening a material such as resin by heat (that is, heat melting), a step of placing the softened material on the separation membrane, and curing the material by cooling. A step of fixing on the separation membrane.

  Examples of the method for arranging the protrusions include coating, printing, spraying, and the like. Examples of the equipment used include a nozzle type hot melt applicator, a spray type hot melt applicator, a flat nozzle type hot melt applicator, a roll type coater, an extrusion type coater, a printing machine, and a sprayer.

(3-4) Formation of separation membrane leaf As described above, the separation membrane leaf may be formed by folding the separation membrane so that the surface on the supply side faces inward, or two separate sheets It may be formed by attaching a separation membrane.

  It is preferable that the manufacturing method of the separation membrane element includes a step of sealing the inner end portion in the surrounding direction of the separation membrane on the surface on the supply side. In the sealing step, the two separation membranes are overlapped so that the surfaces on the supply side face each other. Furthermore, the inner end in the winding direction of the overlapped separation membrane, that is, the left end in FIG. 5 is sealed.

  Examples of the method of “sealing” include adhesion by an adhesive or hot melt, fusion by heating or laser, and a method of sandwiching a rubber sheet. Sealing by adhesion is particularly preferable because it is the simplest and most effective.

  At this time, a supply-side channel material formed separately from the separation membrane may be disposed inside the overlapped separation membrane. As described above, the arrangement of the supply-side flow path material can be omitted by providing a height difference in advance on the supply-side surface of the separation membrane by embossing or resin coating.

  Either the supply-side sealing or the permeation-side sealing (envelope-like membrane formation) may be performed first, or the supply-side sealing is performed while stacking separation membranes. And the sealing of the surface on the transmission side may be performed in parallel. However, in order to suppress the generation of wrinkles in the separation membrane during winding, an adhesive or hot melt at the end in the width direction is allowed so that adjacent separation membranes are allowed to shift in the surrounding direction due to winding. It is preferable to complete the solidification or the like, that is, the solidification for forming an envelope-like film, after the winding is completed.

(3-5) Formation of Envelope-shaped Membrane One separation membrane is folded and bonded so that the transmission side faces inward, or two separation membranes are stacked and bonded so that the transmission side faces inward. Thus, an envelope-like film can be formed. In the rectangular envelope film, the other three sides are sealed so that only one end in the surrounding direction opens. Sealing can be performed by bonding with an adhesive or hot melt, or by fusion with heat or laser.

  The shape and configuration of the sealing portion of the envelope-shaped film thus formed are as described above. In particular, the sealing portion is preferably provided closer to the outer edge of the separation membrane than the region where the permeate-side channel material is formed.

(3-6) Winding of separation membrane A conventional element manufacturing apparatus can be used for manufacturing a separation membrane element. In addition, as an element manufacturing method, a method described in a reference (Japanese Patent Publication No. 44-14216, Japanese Patent Publication No. 4-11928, Japanese Patent Laid-Open No. 11-226366) can be used. Details are as follows.

  When the separation membrane is wound around the water collecting pipe, the separation membrane is arranged so that the closed end of the leaf, that is, the closed portion of the envelope-shaped membrane faces the water collecting pipe. By winding the separation membrane around the water collecting pipe in such an arrangement, the separation membrane is wound in a spiral shape.

  If a spacer such as a tricot or base material is wound around the water collection pipe, the adhesive applied to the water collection pipe will not flow easily when the element is wound, leading to suppression of leakage, and the flow path around the water collection pipe is stable. Secured. The spacer may be wound longer than the circumference of the water collecting pipe.

  When the tricot is wound around the water collecting pipe, the adhesive applied to the water collecting pipe is difficult to flow when the element is wound, leading to suppression of leakage, and further, the flow path around the water collecting pipe is stably secured. The tricot may be wound longer than the circumference of the water collecting pipe.

(3-7) Other steps The method for producing a separation membrane element may include further winding a film, a filament, and the like around the outer periphery of the wound membrane of the separation membrane formed as described above. Further steps such as edge cutting for aligning the end of the separation membrane in the longitudinal direction of the water collecting pipe, attachment of an end plate, and the like may be included.

[4. (Use of separation membrane element)
The separation membrane element may be further used as a separation membrane module by being connected in series or in parallel and housed in a pressure vessel.

  In addition, the separation membrane element and module described above can be combined with a pump that supplies fluid to them, a device that pretreats the fluid, and the like to form a fluid separation device. By using this separation device, for example, raw water can be separated into permeated water such as drinking water and concentrated water that has not permeated through the membrane, and water suitable for the purpose can be obtained.

  The higher the operating pressure of the fluid separator, the higher the removal rate, but the energy required for operation also increases, and considering the retention of the separation membrane element supply channel and permeation channel, the membrane module The operating pressure when passing through the water to be treated is preferably 0.2 MPa or more and 5 MPa or less. As the raw water temperature increases, the salt removal rate decreases. However, as the raw water temperature decreases, the membrane permeation flux also decreases. Moreover, when the pH of the raw water is in a neutral region, even if the raw water is a high salt concentration liquid such as seawater, the generation of scales such as magnesium is suppressed, and the deterioration of the membrane is also suppressed.

  The fluid to be treated by the separation membrane element is not particularly limited, but when used for water treatment, as raw water, TDS (Total Dissolved Solids: total dissolved solids) of 500 mg / L or more and 100 g / L or less such as seawater, brine, drainage, etc. For example). In general, TDS indicates the total dissolved solid content, and is expressed by “mass / volume”, but 1 L may be expressed as 1 kg and may be expressed by “weight ratio”. According to the definition, the solution filtered through a 0.45 μm filter can be calculated from the weight of the residue by evaporating at a temperature of 39.5 to 40.5 ° C., but more simply converted from the practical salt content (S). .

[5. Other forms of separation membrane element]
<Configuration of separation membrane element>
Another embodiment of the separation membrane element will be described. In addition, the above-mentioned matter is applied about the structure which is not mentioned below, a manufacturing process, and utilization.

  In this embodiment, as shown in FIG. 9, the protrusion 3 is fixed to a sheet different from the separation membrane. That is, as shown in FIG. 9, the separation membrane element includes a separation membrane 102; a permeation-side flow path member 14 including a sheet 13 and a protrusion 3 fixed on the sheet 13.

  The separation membrane element of the present embodiment is manufactured by the same method as the separation membrane element including the leaf shown in FIG. 1 except that the separation membrane element includes a step of sandwiching the permeation side channel material between the separation membranes.

<Separation membrane>
Unlike the separation membrane 1 in FIG. 1, the separation membrane 102 does not include the protrusion 3.

<Permeate channel material>
The permeate-side channel material 14 is disposed between the permeate-side surfaces 122 of the two separation membranes 102. More specifically, the two separation membranes 102 are bonded (sealed) in the same manner as the separation membrane 2 and the separation membrane 7 in FIG. It is preferable that the sheet 13 of the permeation-side flow path material 14 exists between the separation membranes in at least a part of the adhesion portion. In FIG. 9, the size of the sheet 13 and the size of the separation membrane 102 are shown to be the same, but actually, the sheet may be larger or the separation membrane may be larger.

<Sheet>
The porosity of the sheet 13 is preferably 20% or more and 90% or less, and particularly preferably 45% or more and 80% or less.

  If the accuracy of the arrangement of the protrusions is insufficient, the groove between the protrusions may be blocked. However, when the porosity of the sheet is 20% or more, the permeated water can move to another groove through the gap of the sheet 13, and the amount of water produced by the separation membrane element increases. Furthermore, since the resin constituting the protrusion 3 can be appropriately impregnated into the sheet 13, peeling of the protrusion 3 from the sheet 13 can be suppressed. Moreover, since the sheet 13 can be appropriately impregnated with the adhesive that seals between the separation membranes, the supply water can be prevented from flowing into the permeate-side flow path.

  Moreover, it can suppress that resin which comprises the protrusion 3 impregnates to the back of the sheet | seat 13 because a porosity is 90% or less. When the resin is impregnated to the back of the sheet 13, the thickness of the sheet 13 becomes uneven at the resin-impregnated portion and the surrounding portion. Moreover, the breadth of the adhesive agent which adhere | attaches leaves can be moderately suppressed because the porosity is 90% or less. As a result, an effective membrane area can be ensured. Thereby, the fall of the amount of fresh water of a separation membrane element can be suppressed.

  Here, the porosity means the ratio of voids per unit volume of the substrate. The porosity is obtained by dividing the value obtained by subtracting the dry weight of the base material from the weight of the pure water contained in the base material by the apparent volume of the base material at the time of drying. Calculated. The thickness of the sheet 13 is preferably 0.2 mm or less. In order to seal between the permeation side surfaces of the two separation membranes, it is preferable that the sheet 13 sandwiched between the separation membranes at the sealing location is impregnated with an adhesive. When the thickness of the sheet 13 is 0.2 mm or less, the adhesive is impregnated throughout in the thickness direction of the sheet 13, so that it is possible to prevent the supply water from being mixed into the permeated water. However, even if the thickness of the sheet 13 exceeds 0.2 mm, the separation membrane can be sealed with an adhesive if the porosity of the sheet 13 is 80% or more. Moreover, since the intensity | strength of the sheet | seat 13 is securable because the thickness of the sheet | seat 13 is 0.02 mm or more, damage to the sheet | seat 13 can be suppressed.

  In particular, if the thickness of the sheet 13 is 0.02 mm or more and 0.2 mm or less, the porosity is preferably 20% or more and 80% or less, and the thickness of the sheet 13 is more than 0.02 mm and 0.4 mm or less. If present, the porosity is more preferably 30% or more and 90% or less.

  Specifically, a nonwoven fabric is preferably used as the sheet 13. As the sheet 13, for example, the same material and structure as the base material of the separation membrane described above are applied.

<Protrusions>
For the protrusions fixed to the sheet, the configuration (that is, the shape, dimensions, arrangement, material, etc.) described for the protrusions fixed to the base material of the separation membrane with reference to FIG. In addition, the permeation side channel material of the present embodiment is manufactured by providing protrusions on the sheet by the same method as that for providing protrusions on the separation membrane.

  The relationship between the height c of the projection and the thickness H1 of the sheet will be described. The ratio (c / H0) of the height c of the protrusions to the sum H0 of the sheet thickness H1 and the height c of the protrusions is preferably 0.05 or more. This is because a wide flow path can be secured. On the other hand, when the ratio (c / H0) is 0.7 or less, the sheet can be prevented from being broken or damaged by the protrusions when the sheet is wound while tension is applied. This is because the larger the ratio (c / H0), the greater the load on the sheet of protrusions and the lower the physical durability of the sheet.

  When the ratio (c / H0) is 0.13 or less, the porosity of the sheet is preferably 30% or more and 90% or less. When the ratio (c / H0) exceeds 0.13 (or 0.15 or more) and is 0.7 or less, the porosity of the sheet is 20% or more and 80% or less. Is preferred.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.

(Sheet thickness and protrusion height)
The thickness of the sheet and the height of the protrusions were measured with a high-precision shape measurement system KS-1100 manufactured by Keyence Corporation. Specifically, the height of the projections was analyzed for average height difference from the measurement result on the transmission side of 5 cm × 5 cm using a high precision shape measurement system KS-1100 manufactured by Keyence Corporation. Thirty points with a height difference of 10 μm or more were measured, and the value obtained by dividing the sum of the height values by the total number of measurement points (30 points) was taken as the height of the protrusion.

(Protrusion-side channel material spacing, projection width, projection height)
Using a high-precision shape measurement system KS-1100 manufactured by Keyence Corporation, the horizontal distance from the apex of the channel material on the permeate side of the separation membrane to the apex of the adjacent channel material was measured at 200 points, and the average value was pitched. Calculated as

  Further, the distances b, e, width d, and length f were measured by the above-described method in the photograph in which the pitch was measured (see FIGS. 2 and 3).

(Sealing property)
About the produced separation membrane element, vacuum suction was performed from the end of the water collection pipe | tube with the pressure of -100 kPa using the vacuum pump. When the degree of vacuum reached 90 kPa (that is, pressure -90 kPa), the cock provided in the pipe connecting the vacuum pump and the separation membrane element was closed to maintain the pressure inside the element. Thereafter, the sealing property of the element was evaluated according to the following criteria. The higher the element vacuum after 25 seconds, the higher the sealing performance. In the present invention, “excellent” and “good” were determined to be acceptable.
Good: Element vacuum after 25 seconds is 50 kPa or higher Impossibility: Element vacuum after 25 seconds is 50 kPa or lower.

  The above evaluation was carried out on 15 elements, and the most obtained result was regarded as durability.

(Adhesive consumption)
The adhesive was applied to the tank while being discharged into the tank at a rate of 3 g / sec. By measuring the weight before and after application in the tank, the amount used was calculated from the following formula.
Adhesive consumption (g) = Adhesive weight before use (g)-Adhesive weight after use (g)
Example 1
A 15.0 wt% DMF solution of polysulfone on a non-woven fabric made of polyethylene terephthalate fibers (yarn diameter: 1 dtex, thickness: about 0.09 mm, density 0.80 g / cm 3) at a thickness of 180 μm at room temperature (25 ° C.) The porous support layer (thickness 0.13 mm) made of a fiber-reinforced polysulfone support membrane was prepared by immediately immersing it in pure water and leaving it for 5 minutes, and then immersing it in warm water at 80 ° C. for 1 minute. .

  Thereafter, the porous support layer roll was unwound, and 1.9% by weight of m-PDA (metaphenylenediamine) and 4.5% by weight of ε-caprolactam were applied to the polysulfone surface, and nitrogen was blown from the air nozzle. After removing the excess aqueous solution from the surface of the support film, an n-decane solution at 25 ° C. containing 0.06% by weight of trimesic acid chloride was applied so that the surface was completely wetted.

  Then, the excess solution was removed from the membrane by air blow and washed with hot water at 50 ° C. to obtain a separation membrane roll.

  The separation membrane thus obtained was folded and cut so that the effective membrane area at the separation membrane element was 37.0 m 2, and the net (thickness: 0.66 mm, pitch: 5 mm × 5 mm, fiber diameter: 330 μm, ) As a supply-side channel material, 26 leaves having a width of 900 mm and a leaf length of 800 mm were produced.

  On the other hand, the separated protrusions and the protrusion group were formed into a sheet. That is, when a separation membrane element is used while adjusting the temperature of a backup roll to 20 ° C. using an applicator loaded with a comb-shaped shim having a slit width of 0.35 mm and a pitch of 0.7 mm, it is perpendicular to the longitudinal direction of the water collecting pipe. In the case of an envelope-like membrane, a highly crystalline PP (MFR 1000 g / 10 min, melting point 161 ° C.) linearly perpendicular to the longitudinal direction of the water collecting pipe from the inner end to the outer end in the surrounding direction. A composition pellet consisting of 60% by weight and 40% by weight of a low crystalline α-olefin polymer (Idemitsu Kosan Co., Ltd .; low stereoregular polypropylene “L-MODU · S400” (trade name)) was obtained at a resin temperature of 205 ° C. It was applied linearly at a running speed of 11 m / min. One spacing protrusion was provided at each end in the width direction. The sheet had a thickness of 50 μm, a basis weight of 25 g / m 2, and an embossed nonwoven fabric (pattern: staggered diamond type, pitch 20 mm).

  It was as Table 1 of the shape of the protrusion in the space | interval protrusion obtained and the protrusion group.

  A permeate-side channel material is laminated on the permeate side surface of the obtained leaf, and is collected on an ABS (acrylonitrile-butadiene-styrene) water collecting pipe (width: 1,020 mm, diameter: 30 mm, number of holes 40 holes × straight line). The film was wound in a spiral shape, and a film was further wound around the outer periphery. After fixing with tape, edge cutting, end plate attachment, and filament winding were performed to produce a separation membrane element having a diameter of 8 inches. Both end plates were perforated end plates. The separation membrane element was put in a pressure vessel and operated at an operating pressure of 0.7 MPa, an operating temperature of 25 ° C. and a pH of 6.5 using a NaCL aqueous solution having a concentration of 1,050 mg / L and pH 6.5 (recovery rate 15%). Table 1 shows the amount of water produced, the salt rejection, and the amount of leaf adhesive used.

(Examples 2 to 4)
A separation membrane element was produced in the same manner as in Example 1 except that the projection group and the separated projection shape were changed as shown in Table 1.

  The sealing properties and the amount of leaf adhesive used were as shown in Table 1.

(Example 5)
The shape of the projections is as shown in Table 1, all are the same as in Example 1 except that the separation projections and the projection group are provided on the permeation side of the separation membrane, and the sheet-like permeation-side channel material is not disposed. Thus, a separation membrane element was produced.

  When the separation membrane element was put in a pressure vessel and operated under the above conditions to obtain permeated water, the sealing properties and the amount of leaf adhesive used were as shown in Table 1.

(Comparative Example 1)
A separation membrane element was produced in the same manner as in Example 1 except that no separation protrusion was formed.

  When the separation membrane element was put in a pressure vessel and operated under the above conditions to obtain permeated water, the sealing properties and the amount of leaf adhesive used were as shown in Table 1.

(Comparative Example 2)
A separation membrane element was produced in the same manner as in Example 1 except that the interval between the protrusion group 3 and the separation protrusions was changed as shown in Table 1.

  When the separation membrane element was put in a pressure vessel and operated under the above conditions to obtain permeated water, the sealing properties and the amount of leaf adhesive used were as shown in Table 1.

  As is apparent from the results shown in Table 1, the separation membrane elements of Examples 1 to 5 of the present invention can obtain a sufficient amount of permeated water having a high desalination rate even when operated for a long time. It can be said that it has excellent separation performance stably.

  The membrane element of the present invention can be suitably used particularly for brine or seawater desalination.

1, 7 Separation membrane 2 Separation membrane body 3 Protrusion 4 Separation membrane leaf 5
51 Distance between separation protrusion and protrusion group 6 Water collecting pipe 8 Separation membrane pair 13 Sheet a Length of separation membrane body b Distance between channel members in width direction c Height of projection d Width of projection e Width direction Interval between channel materials at f f Projection length 21 Supply side surface 22 Permeation side surface 31 Collective projection 32 Separation projection 71 Supply side surface 81 End plate 82 End plate 83, 85 Raw water hole 84, 86 Center hole Width of W0 projection group W1 Distance between spaced projections and projection group 100 Separation membrane element 201 Base material 202 Porous support layer 203 Separation functional layer

Claims (3)

Water collecting pipe,
A separation membrane having a supply side surface and a permeate side surface and wound around the water collection pipe;
A plurality of protrusions provided on the permeation side surface of the separation membrane, and a separation membrane element comprising:
As the protrusion, a protrusion group and a separation protrusion are provided,
The spaced protrusion is disposed outside at least one end of the protrusion group in the longitudinal direction of the water collecting pipe,
The interval between the protrusions in the protrusion group is 0.1 mm or more and 1.0 mm or less,
A separation membrane element, wherein a distance between the projection group and the separation projection in the longitudinal direction of the water collecting pipe is 10 mm or more and 50 mm or less. A water collecting pipe, a separation membrane having a supply side surface and a permeation side surface and wound around the water collecting pipe;
A separation membrane element comprising: a sheet disposed on a permeation side surface of the separation membrane; and a permeation-side flow path member composed of a plurality of protrusions fixed to the sheet,
The protrusion is composed of a protrusion group and a separation protrusion,
The spaced protrusion is disposed outside at least one end of the protrusion group in the longitudinal direction of the water collecting pipe,
The interval between the protrusions in the protrusion group is 0.1 mm or more and 1.0 mm or less,
A separation membrane element, wherein a distance between the projection group and the separation projection in the longitudinal direction of the water collecting pipe is 10 mm or more and 50 mm or less. The separation membrane element according to any one of claims 1 to 2, wherein a height of the separation protrusion and a height of the protrusion group are 0.1 mm or more and 1.0 mm or less.

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